Field of the Invention
The present invention relates to a control apparatus for a vehicle, and particularly, to an apparatus applied to an engine provided with a valve operation mechanism that can stop an intake valve and an exhaust valve in a closed state during rotation of an output shaft of the engine.
Description of the Related Art
There is well known a valve operation mechanism that can stop an intake valve and an exhaust valve in a closed state during rotation of an output shaft of an engine. In the engine provided with this type of valve operation mechanism, in a state of connecting the engine and driving wheels with engagement of a clutch, an operation of the intake valve and an operation of the exhaust valve of the engine are stopped in a closed state, making it possible to perform an inertial running of the vehicle without executing fuel supply to the associated cylinders in the engine (for example, Japanese Patent Laid-Open No. 2014-091398). This running mode is called “valve stop inertial running” as needed in the present specification.
During execution of the valve stop inertial running, the clutch in the power transmission route is made to be in a connecting state. Therefore, the output shaft of the engine and pistons connected thereto are driven by power transmitted from the driving wheels. In this valve stop inertial running, as compared with an inertial running in a state of no valve stop, a so-called pumping loss is reduced. Therefore, an engine brake force is reduced to increase a free running distance (that is, a running distance by inertia) and reduce opportunities of fuel resupply, making it possible to contribute to an improvement on fuel efficiency. Further, in a case where a hydraulic pressure by a mechanical oil pump driven by an engine is used in the other devices (automatic transmission or the like), the supply of the hydraulic pressure can continue regardless of the valve stopping.
In the valve stop inertial running, the piston is driven by a rotational force from the driving wheel side without use of a driving force generated in the piston. In contrast to this, a running mode of operating (i.e. activating) the intake valve and the exhaust valve during rotation of the output shaft of the engine (in other words, regular running) is called “valve operation running” as needed in the present specification.